A stamping press has upper and lower die assemblies for shaping sheet metal. Typically, the lower die assembly includes a center post mounted on a lower die. A lower ring surrounds the post and is mounted on the lower die for vertical movement. Air cushion pins projecting through holes in the lower die press the ring upwardly. Guide pins guide the vertical movement of the ring. The post and ring cooperate with an adapter on the upper die assembly to shape sheet metal. Provision should be made for preventing the ring from becoming separated from the lower die, for avoiding interference between the air pins and the guide pins, and for holding the ring when the ring needs machining or spotting. All this should be done a simpler and more economical manner than anything heretofore known in the prior art.